1. Technical Field
This invention is related to the field of memory implementation, and more particularly to the implementation of sense amplifiers.
2. Description of the Related Art
Computing systems may include one or more systems on a chip (SoC), which may integrate a number of different functions, such as, graphics processing, and memories onto a single integrated circuit. With numerous functions included in a single integrated circuit, chip count may be kept low in mobile computing systems, such as tablets, for example, which may result in a smaller form factor for such mobile computing systems.
Memories typically include a number of data storage cells composed of interconnected transistors. Such data storage cells may be constructed according to a number of different circuit design styles. For example, the data storage cells may be implemented as a single transistor coupled to a capacitor to form a dynamic storage cell. Alternatively, cross-couple inverters may be employed to form a static storage cell, or a floating gate MOSFET may be used to create a non-volatile storage cell.
During the semiconductor manufacturing process, variations in lithography, transistor dopant levels, etc., may result in different electrical characteristics between storage cells and sense amplifiers that are intended to have identical characteristics. Additional variation in electrical characteristics may occur due to aging effects within the transistors as the device is repeatedly operated. These differences in electrical characteristics between transistors can result in data storage cells that output different small signal voltages for the same stored data, and sense amplifiers that respond differently to the same differential input voltage level.
In some cases, the variation of a given sense amplifier may result in the sense amplifier not being able to properly sense the data state of a selected storage cell. Such sense amplifiers may be identified as failures during testing and may require re-design in order to achieve manufacturing yield goals.